Forrestania’s camp of nickel sulphide deposits is hosted by a sequence of ~2.9Ga meta-igneous and metasedimentary rocks that are part of the Forrestania Greenstone Belt (FGB) of the Youanmi Terrane of the Eastern Yilgarn Craton.

Forrestania’s nickel deposits is the ‘Kambalda-style’ Type 1 and Type 2 models where nickel sulphides are interpreted to have accumulated in channelised komatiitic lava flows. Many of Forrestania’s deposits are often tectonically displaced from the original depositional locations and have been deformed and/or dismembered by one or more local and/or regional post-depositional tectonic events.

The main deposit type is the komatiite hosted, disseminated to massive nickel sulphide deposits, which include the Flying Fox and Spotted Quoll deposits. The mineralisation occurs in association with the basal section of high MgO cumulate ultramafic rocks.

The greenstone succession in the district also hosts several orogenic lode gold deposits, of which the Bounty Gold Mine is the largest example.

Flying Fox is Western Areas first producing underground mine and remains one of the highest grade nickel mines in the world. Production commenced in 2006, and the underground mine now operates at depths of over 1km underground.

The Flying Fox orebody extends from 250m to 1.2km below the surface and includes discrete independent orebodies with possible extensions at depth. The primary stoping method used is ‘top- down’ long-hole stoping using paste-fill to attempt 100% recovery of the high-grade orebody. In the narrower sections of the orebody both modified Avoca with unconsolidated and cemented rock-fill are used.

The Spotted Quoll orebody is open at depth with the mine currently planned to just over 1km below the surface. The primary stoping method is a ‘top-down’ mining method using long-hole open stoping with paste fill. The narrower and shallower areas are mined using top-down narrow vein techniques.

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The high-grade nickel ore mined from Forrestania is processed through the Cosmic Boy Concentrator (CBC) and sold into offtake agreements with Jinchuan Group, China’s largest stainless steel producer and BHP Ni West.

The CBC treats the raw nickel and produces a consistent nickel concentrate product grading approximately 14% nickel. The concentrate produced from the Forrestania project is characterised by low impurities such as magnesium which makes it more desirable to smelters.

The concentrator consists of a three-stage crushing circuit, followed by a single closed-circuit ball mill and a system of flotation tanks and thickening/filtration system.

The recovery rates for Cosmic Boy currently average between 85% and 90%. The recovery rates refer to the percentage amount of nickel recovered from the raw ore during processing.

At CBC a Mill Recovery Enhancement Project (MREP) has recently been commissioned. The MREP incorporates the use of the C ........